Clientdatasets don't seem to help (speed) when updating MS SQL

Hi everyone,

We need to edit one field for almost every record in a large ordered
query on a MS SQL database.
We thought we'd use ClientDataSets to speed up things.
The update is now much faster, but when we use ApplyUpdates at the end
to write the
changes back to the database, this takes so long that we don't gain any
speed.

Note:
At the beginning of the ApplyUpdates the server's CPU utilization is at
70%, but it drops as the process continues. The number of SQL
compilations drops too. This indicated that the workstation is the
bottleneck.

Is there something crucial we're overlooking? Some magic setting?

Thanks in advance for all tips,
Jan